package com.yuyu.good.remote.config;

import com.netflix.hystrix.HystrixThreadPoolKey;
import com.netflix.hystrix.HystrixThreadPoolProperties;
import com.netflix.hystrix.strategy.HystrixPlugins;
import com.netflix.hystrix.strategy.concurrency.HystrixConcurrencyStrategy;
import com.netflix.hystrix.strategy.concurrency.HystrixRequestVariable;
import com.netflix.hystrix.strategy.concurrency.HystrixRequestVariableLifecycle;
import com.netflix.hystrix.strategy.eventnotifier.HystrixEventNotifier;
import com.netflix.hystrix.strategy.executionhook.HystrixCommandExecutionHook;
import com.netflix.hystrix.strategy.metrics.HystrixMetricsPublisher;
import com.netflix.hystrix.strategy.properties.HystrixPropertiesStrategy;
import com.netflix.hystrix.strategy.properties.HystrixProperty;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
import org.springframework.web.context.request.RequestAttributes;
import org.springframework.web.context.request.RequestContextHolder;

import java.util.concurrent.BlockingQueue;
import java.util.concurrent.Callable;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

/**
 * @author
 * @version 1.0
 * @description: TODO
 * @date 2022/10/10 13:48
 */
@Slf4j
@Component
public class RequestAttributeHystrixConcurrencyStrategy extends HystrixConcurrencyStrategy {

        private HystrixConcurrencyStrategy delegate;

        public RequestAttributeHystrixConcurrencyStrategy() {
            try {
                    log.info("加载RequestAttributeHystrixConcurrencyStrategy");
                this.delegate = HystrixPlugins.getInstance().getConcurrencyStrategy();
                if (this.delegate instanceof RequestAttributeHystrixConcurrencyStrategy) {
                    // Welcome to singleton hell...
                    return;
                }
                HystrixCommandExecutionHook commandExecutionHook = HystrixPlugins
                        .getInstance().getCommandExecutionHook();
                HystrixEventNotifier eventNotifier = HystrixPlugins.getInstance()
                        .getEventNotifier();
                HystrixMetricsPublisher metricsPublisher = HystrixPlugins.getInstance()
                        .getMetricsPublisher();
                HystrixPropertiesStrategy propertiesStrategy = HystrixPlugins.getInstance()
                        .getPropertiesStrategy();
                this.logCurrentStateOfHystrixPlugins(eventNotifier, metricsPublisher,
                        propertiesStrategy);
                HystrixPlugins.reset();
                HystrixPlugins.getInstance().registerConcurrencyStrategy(this);
                HystrixPlugins.getInstance()
                        .registerCommandExecutionHook(commandExecutionHook);
                HystrixPlugins.getInstance().registerEventNotifier(eventNotifier);
                HystrixPlugins.getInstance().registerMetricsPublisher(metricsPublisher);
                HystrixPlugins.getInstance().registerPropertiesStrategy(propertiesStrategy);
            }
            catch (Exception e) {
                    log.error("Failed to register Sleuth Hystrix Concurrency Strategy", e);
            }
        }

        private void logCurrentStateOfHystrixPlugins(HystrixEventNotifier eventNotifier,
                                                     HystrixMetricsPublisher metricsPublisher,
                                                     HystrixPropertiesStrategy propertiesStrategy) {
            if (log.isDebugEnabled()) {
                    log.debug("Current Hystrix plugins configuration is ["
                            + "concurrencyStrategy [" + this.delegate + "]," + "eventNotifier ["
                            + eventNotifier + "]," + "metricPublisher [" + metricsPublisher + "],"
                            + "propertiesStrategy [" + propertiesStrategy + "]," + "]");
                log.debug("Registering Sleuth Hystrix Concurrency Strategy.");
            }
        }

        @Override
        public <T> Callable<T> wrapCallable(Callable<T> callable) {
                RequestAttributes requestAttributes = RequestContextHolder.getRequestAttributes();
            return new WrappedCallable<>(callable, requestAttributes);
        }

        @Override
        public ThreadPoolExecutor getThreadPool(HystrixThreadPoolKey threadPoolKey,
                                                HystrixProperty<Integer> corePoolSize,
                                                HystrixProperty<Integer> maximumPoolSize,
                                                HystrixProperty<Integer> keepAliveTime, TimeUnit unit,
                                                BlockingQueue<Runnable> workQueue) {
            return this.delegate.getThreadPool(threadPoolKey, corePoolSize, maximumPoolSize,
                    keepAliveTime, unit, workQueue);
        }

        @Override
        public ThreadPoolExecutor getThreadPool(HystrixThreadPoolKey threadPoolKey,
                                                HystrixThreadPoolProperties threadPoolProperties) {
            return this.delegate.getThreadPool(threadPoolKey, threadPoolProperties);
        }

        @Override
        public BlockingQueue<Runnable> getBlockingQueue(int maxQueueSize) {
            return this.delegate.getBlockingQueue(maxQueueSize);
        }

        @Override
        public <T> HystrixRequestVariable<T> getRequestVariable(
                HystrixRequestVariableLifecycle<T> rv) {
            return this.delegate.getRequestVariable(rv);
        }

        static class WrappedCallable<T> implements Callable<T> {

            private final Callable<T> target;
            private final RequestAttributes requestAttributes;

            public WrappedCallable(Callable<T> target, RequestAttributes requestAttributes) {
                    this.target = target;
                this.requestAttributes = requestAttributes;
            }

            @Override
            public T call() throws Exception {
                try {
                        RequestContextHolder.setRequestAttributes(requestAttributes);
                    return target.call();
                }
                finally {
                        RequestContextHolder.resetRequestAttributes();
                }
            }
        }
    }

